Troops pounded a rebel hideout near Damascus as renewed violence across Syria killed at least four people on Wednesday, among them three soldiers and one civilian, a rights watchdog said.

Clashes between regime forces and armed rebel groups in the village of Marata village, northwestern Idlib province, killed one soldier as he tried to flee the shooting, said the Syrian Observatory for Human Rights.

The United Nations has information that arms are being smuggled in both directions between Lebanon and Syria, a U.N. Middle East envoy said Tuesday.

The envoy, Terje Roed-Larsen, said the Middle East is seeing a spiraling "dance of death" because of the conflict in Syria as President Bashar Assad confronts opponents.

The United States is determined to increase pressure on Syria's President Bashar Assad to make him stand down, the U.S. envoy to the United Nations said Tuesday.

"The situation in Syria remains dire, especially for the millions who continue to endure daily attacks and are in urgent need of humanitarian assistance," ambassador Susan Rice told reporters after a Security Council briefing by U.N.-Arab League envoy Kofi Annan.

Nearly 12,000 people, the majority of them civilians, have been killed in Syria since the outbreak in March 2011 of a revolt against the regime of Bashar al-Assad, a watchdog said Tuesday.

Rami Abdel Rahman, head of the Syrian Observatory for Human Rights, said that of those killed, some 800 had died since a U.N.-backed ceasefire went into effect on April 12.

U.N.-Arab League envoy Kofi Annan said on Tuesday his peace plan could be the last chance to avoid civil war in Syria, where a truce has failed to end 14 months of bloodshed that monitors say has killed nearly 12,000 people.

Annan told the U.N. Security Council that the priority in Syria is "to stop the killing," and expressed concern that torture, mass arrests and other human rights violations are intensifying.

Iran said on Tuesday parliamentary elections in Syria held by the regime of President Bashar Assad was a step towards reform, but expressed regret the vote was shunned by opposition groups.

Foreign ministry spokesman Ramin Mehmanparast told reporters in his weekly briefing that "the vote is the second step the Syrian government is taking in the path of reform," after Assad's promise of launching reforms.

The International Committee of the Red Cross on Tuesday to step up its aid to Syria, where thousands have died in a 14-month bloody uprising against the regime.

The group, which has been working alongside the Syrian Arab Red Crescent to bring humanitarian relief to about 1.5 million people affected by the bloodshed, said it needed the extra $27 million to expand its efforts.

Syrian forces Tuesday swept through a village in Idlib province, firing shells and bursts of gunfire in which two civilians were killed, while another man was shot dead by snipers in Homs, a watchdog said.

The overnight military raid in al-Tamanaa village killed a man and a 50-year-old woman, the head of the Britain-based Syrian Observatory for Human Rights, Rami Abdel Rahman, told Agence France Presse.

International powers are "in a race against time" to prevent all-out civil war in Syria, where the government could use the presence of ceasefire observers to prepare a new assault, U.N. leader Ban Ki-moon warned Monday.

Speaking ahead of a key U.N. Security Council meeting on Syria on Tuesday, Ban again condemned the "brutality" of President Bashar Assad's forces but said attacks by opposition groups have also "escalated."

The United States said Monday Syria's parliamentary election "borders on ludicrous" as the regime of President Bashar Assad continues its violent crackdown on its people.

"It's not really possible to hold credible elections in a climate where basic human rights are being denied to the citizens and the government is continuing to carry out daily assaults ...on its own citizens," State Department deputy spokesman Mark Toner said.